Device for taking a sample of subcutaneous tissue cells from a body

ABSTRACT

Device for taking a sample of subcutaneous tissue cells from a body, comprising a disposable injection syringe with a cylinder, a plunger slidably arranged in the cylinder and connected to an actuating shaft protruding outside the cylinder at one end, and a coupling element situated at the opposite end of the cylinder for the coupling thereto of an injection needle. The device further comprises pulling means for the exerting of a force on the plunger in the direction away from the coupling element. The pulling means comprise on one side energy transmitting biasing means coupled to the cylinder which exerts a tensile force on the plunger which after a movement of the plunger in the order of magnitude of 1 cm from an outer most position in contact with the end of the cylinder bearing the coupling element lies in the order of magnitude of 10 Newton times the diameter of the cylinder in cm 2 .

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to a device for taking a sample oftissue cells from a body and more particularly a syringe for taking asample of subcutaneous tissue cells from a body.

2. Description of the Prior Art

Such a device is known from International patent application WO88/01882. The pulling means for exerting a force on the plunger in thedirection away from the coupling element are formed by a holder whereina disposable injection syringe can be accomodated. A first holder partof this known holder comprises a hand grip with a support connectedthereto at a distance by guiding rods for the second holder part intowhich the cylinder of a disposable injection syringe with the fingerrest protruding transversely thereto can be clamped fixedly. The secondholder part is provided with an opening in which can grip two fingers ofa hand holding the hand grip. Using an injection syringe arranged inthis holder a suction action can be applied instead of the usualinjecting action. Such a suction action is for example applied in takinga sample of cell material, in particular for the purpose of cytologicaltesting. This testing can be used for determining whether a tumour isbenign or malignant. For the collection of the cell material the needleof the injection syringe is inserted into the tumour after which theplunger of the syringe is drawn out so that an underpressure is createdin the syringe and an amount of cell material is sucked into the needle.It is usual in collecting the cell material to move the needle back andforth a number of times so that sufficient cell material is released.The quantity of the collected material is otherwise usually very limitedand then substantially to the capacity of the needle itself.

In order to avoid the material being drawn into the cylinder forcibly bythrough-flowing air and becoming so spread out there that it is nolonger usable for the test, the underpressure must first be neutralizedagain by moving back the plunger before removing the needle.

The known holder is awkward in use. On withdrawal of the plunger acramped hand position arises which either makes difficult a sensitiveand controlled guidance of the injection syringe needle or makes itimpossible. Moreover, the distance from the hand to the area where theneedle is inserted is great so that precise and sensitive handling isalso made difficult as a result. Further, the assembly of holder withdisposable injection syringe is bulky and in the position of use is infact held in the same position as a pistol, which has an at leastdisturbing effect on the patient being treated.

SUMMARY OF THE INVENTION

The aim of the invention is to provide a holder of the present sortwhich obviates these drawbacks. This aim is achieved according to theinvention with the steps mentioned subsequently herein. After insertionof the injection needle the biasing means provide the generating of thesuction. With only a limited displacement of the plunger from theoutermost position an equilibrium is created between the force exertedon the plunger by the underpressure generated and the force exerted bythe biasing means. Because of this the device can be held in a morerelaxed manner. This enables sensitive control and use of the device.

Underlying the invention to a significant extent is the insight that theplunger of the injection syringe does not need to be withdrawn to themaximum, as is usual, but only for a very limited distance in order togenerate suction suitable for the removal of the cell material. Becausethe distance through which the plunger is withdrawn is relatively smallthe device can also take a small form and this contributes to sensitivehandling of the device and moreover the more compact form thereof isexperienced by the patient as less threatening.

As a result of the present invention it becomes unnecessary during theinsertion of the injection needle to exert a force countering thebiasing means so that the insertion of the needle can be performed withthe very desirable sensitivity.

Achieved in a very favourable manner with the present invention is thatduring use of the device it is ensured that when the plunger is made tomove back into the cylinder of the injection syringe at the end of theoperation the plunger is prevented from being pressed downward withpositive force which could result in the possibility that the collectedcell material is pressed out of the injection needle again. When thefinger rest is pressed in the plunger moves back until the underpressureunder the plunger is removed. Should the finger rest be pressed infurther the plunger is not pressed further downward by the free strokein the transmission.

The device is preferably embodied in its entirety as a disposable devicefor once-only use.

A favourable alternative embodiment of the device is disclosed. Bymaking use of standard disposable injection syringes usage costs can belowered.

In a preferred embodiment of the invention the portion of the plungeradjoining the injection needle protrudes out of the passage opening andtherefore remains in sight during use. The operation can for example beadapted as a result should it be apparent that fluid is being drawn up.

The finger rest arranged according to the present invention is situatedrelatively close to the end of the injection syringe bearing theinjection needle, which contributes to a good and sensitive control ofthe assembly.

When using the present invention the holder with injection syringe canbe held in position in the hand in a natural manner which againcontributes to its user friendly character.

In the present invention the transport with the free stroke can still beachieved in a simple and reliable manner.

It should be noted that an injection syringe provided with biasing meansin the form of a spring is known from American patent specification U.S.Pat. No. 4,641,663. This known injection syringe is not suitable fortaking a sample of subcutaneous tissue cells but is intended for thedrawing up of a quantity of liquid. Only a limited amount of springforce is needed to draw up liquid and moreover the plunger can be movedthrough a relatively great distance by the spring.

The invention will be further elucidated in the following description ofa number of embodiments.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows in partly sectional perspective view a device according tothe invention in the embodiment of a holder having accommodated thereina standard disposable injection syringe.

FIG. 2 shows a portion of another embodiment of the device in FIG. 1.

FIGS. 3a-d show schematically the action of the device from FIGS. 1 and2.

FIG. 4 shows in partially broken away perspective view a deviceaccording to the invention in the embodiment of a disposable device foronce-only use.

FIGS. 5a-e show schematically the action of the device according to FIG.4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the device according to the invention shown in FIG. 1 a disposableinjection syringe 2 is accommodated in the holder 1. The disposableinjection syringe 2 consists in the generally known way of a cylinder 3,a plunger 4 arranged slidably in the cylinder 3 and connected with anactuating shaft 5 protruding outside the cylinder 3 at one end and aninjection needle 9 coupled thereto by a coupling element 8 at the end ofthe cylinder 3 situated opposite the protruding actuating shaft end. Theactuating shaft 5 bears at its protruding end a thumb rest 6 whilefinger rests 7 are formed at the end lying close to the cylinder 3.

The holder 1 comprises a first holder part 12 wherein the cylinder 3 ofthe disposable injection syringe can be fixed. This first holder part 12comprises a sleeve-like body 13 connected fixedly to an end plate 14.The end plate 14 is provided with a passage opening 16 through which theend of the cylinder 3 bearing the needle 9 can protrude. At the oppositeend the sleeve-like member 13 carries gripping means 15 which can clampthe finger rests 7 on the cylinder 3. These gripping means 15 areembodied such that these act as a bayonet closure whereby the disposablesyringe 2 can be fixed very simply in the holder.

Connected to the end plate 14 are two guiding pins 18 which extendparallel to the longitudinal direction of the holder. A second holderpart 19 comprises sleeves 20 with which this second holder part 19 isslidably mounted onto the pins 18 of the first holder part 12. Thebottom guide sleeve 20 of the second holder part 19 in FIG. 1 carries aclosing plate 22 hinging at 23. The closing plate 22 is provided on theopposite side with a slot 25 which can grip around the shank of a wingscrew 24. The closing plate 22 can be fixed in position with the wingscrew 24 which grips into the uppermost sleeve 20. The closing plate 22protrudes beneath the thumb rest 6 of the actuating shaft 5 and can thusgrip this thumb rest 6.

Coil springs 21 are arranged in the sleeves 20. These coil springs 21form biasing means which can force the gripping means 15, 22 of thefirst and second holder part 12, 19 away from one another. In otherwords the springs 21 force the second holder part 19 to the right asseen in FIG. 1 relative to the first holder part 12. When an injectionsyringe 2 is arranged in the holder 1 the plunger 4 is then loadedthereby in the sliding out direction.

The holder 1 with the disposable injection syringe 2 arranged therein isheld with one hand in the manner usual for an injection syringe, wherebythe thumb rests on the thumb rest 6 and the index and middle fingerrespectively on either side of the sleeve-like member 13 on the fingerrest 17 arranged on this member 13.

As shown in FIG. 1 the finger rest 17 is arranged at a distance from thegripping means 15 on the side away from the closing plate 22. Thuscreated during use is a suitable distance between the finger rest 17 andthe thumb rest 6 which is favourable for controlled handling of theholder with syringe. The hand in which the holder is held is moreoverlocated relatively close to the injection needle 9 so that during usesensitive and accurate control of the assembly is possible.

As shown the second holder part 19 bears a ratchet bracket 26 which cangrip onto a ratchet projection 27 on the end plate 14 of the firstholder part 12. The ratchet bracket 26 is of a length such that theholder parts 12, 19 can be blocked counter to the force of the springs21 in the position whereby the gripping means 15, 22 are closest to eachother, that is, in the position whereby in use the plunger 4 is entirelypushed into the cylinder 3.

It will be apparent that the disposable syringe 2 is arranged in theholder 1 as seen in FIG. 1 on the right-hand side thereof, whereby theclosing plate 22 is swivelled away about the hinge 23. After theinsertion of the cylinder 3 in the sleeve-like member 13 and turningthereof through a limited angle such that the finger rests 7 engage withthe gripping means 15 the closing plate 22 is swivelled back to theposition shown in FIG. 1 and secured using the screw 24. When theplunger is subsequently pushed completely into the cylinder 3 and theratchet bracket 26 is brought into engagement with the ratchetprojection the assembly is in the ready-for-use position.

In FIG. 3a the assembly is schematically shown in this read-for-useposition. The use of the holder according to the invention is asfollows.

In the ready-for-use position as described above the holder havingtherein a disposable injection syringe 2 is inserted with its needle 9into tissue 31 in order to remove a quantity of cell material therefrom.The holder according to the invention is particularly but notexclusively intended for removal of a quantity of cell material from atumour 30 in order that cytological testing can be carried out on thatcell material.

As previously noted, the holder parts are temporarily blocked during theinsertion of the injection needle 9 into the tumour 30 by the ratchet 26counter to the force of the biasing means formed by the springs 21. Theinsertion can therefore be performed with great sensitivity since theforces arising during insertion are not masked by forces for thetensioning of the springs 21.

After insertion, as is shown in FIG. 3b, the thumb rest 6 is pushed in ashort distance 32 in the direction of the arrow 33, as a result of whichthe ratchet 26 can be released. The ratchet 26 can be spring loaded sothat it automatically springs loose. The ratchet can also be released byhand.

Subsequently, as shown in FIG. 3c, the force on the thumb rest 6 isreduced causing the springs 21 to displace the first holder part to theright. The closing plate 22 thereby grips under the thumb rest 6 and theplunger 4 is therefore also moved in the cylinder 3 to the right. Thesprings 21 are preferably dimensioned such that an equilibrium of forcesresults as soon as the plunger 4 is withdrawn a distance in the order ofmagnitude of 1 cm. For this purpose the springs are dimensioned suchthat after a displacement in the direction of the arrow 35 over adistance 35 in the order of magnitude of 1 cm they exert a force in theorder of magnitude of 10 Newton times the diameter of the cylinder incm².

In the position of FIG. 3c the injection needle 9 is now moved back andforth a small distance in the tumour 30 as a result of which an amountof cell material 36 is freed which is sucked up in the needle 9. Again,the hand holding the holder does not hereby need to exert force tomaintain the underpressure so that these operations can also be executedwith precision, control and sensitivity.

When sufficient cell material has been taken up the thumb rest 6 ispressed in again and the ratchet 26 is fixed in place. The underpressurein the cylinder is then hereby removed. The assembly can be subsequentlywithdrawn.

The cell material 36 collected in the needle 9 is further processed inthe usual manner.

It is further noted that it is necessary for the underpressure to beremoved before the needle is withdrawn in order to prevent cell material36 being sucked into the cylinder forcibly through air being sucked in,which would make it practically impossible to remove this material fromthe disposable syringe for testing. This is otherwise per se known.

FIG. 2 shows a modification of the holder in FIG. 1. The correspondingparts are indicated with the same reference numerals so that furtherdiscussion thereof can be omitted. In relation to the embodiment in FIG.1 a thumb rest 37 is arranged on the closing plate 22 protruding abovethe thumb rest 6 on the actuating shaft 5 and leaving free a space 38 ofsome millimetres above the thumb rest 6 on the actuating shaft 5. Thisthumb rest 37 is indicated schematically in FIGS. 3a-d with dashedlines. The thumb of the operating hand rests on this thumb rest 37during use.

As discussed, at the end of the operation just before the withdrawal ofthe needle 9, the plunger 4 must move back into the cylinder 3 in orderto remove the underpressure. This is performed by pushing back thesecond holder part counter to the force of the springs 21 in thedirection of the arrow 39. As a result of the free stroke for the thumbrest 6 provided by the thumb rest 37 is now achieved that the plunger 4moves back only under the influence of the underpressure and thereforedoes not move further once this underpressure is removed. The secondholder part can still be moved slightly, which can be necessary forcausing the ratchet 26 to grip. Since the plunger 4 only moves backunder the influence of the underpressure and not because of a forceapplied to the thumb rest 6, partial pressing of the collected cellmaterial 36 out of the needle 9 is prevented.

The device 50 as shown in FIG. 4 is of the type embodied as disposabledevice for once-only use. The device 50 comprises a cylinder 51, aplunger 54 slidably arranged in the cylinder 51 and connected in amanner further to be described to an actuating shaft 55 which protrudesoutward from the cylinder 51 at the right-hand end as seen in FIG. 4 andwhich carries a thumb rest 56 at its end. At the opposite end thecylinder is provided in the usual manner with a coupling element 52 forcoupling a needle 53 to the cylinder 51.

Arranged around the end of the actuating shaft 55 protruding out of thecylinder 51 is a spiral spring 57 which lies on one side against thecylinder 51 and on the other side against the underside of the thumbrest 56. The spring 57 can exert a force on the plunger 54 via theactuating shaft 55 in the direction away from the coupling element 52.

As shown the shaft 55 and therefore the finger rest 56 are coupled tothe plunger 54 by a transmission with a free stroke. The shaft 55 bearson its end facing the plunger two cams 58 which grip into slots 59 whichare formed in rearwrd facing protrusions connected to the plunger 54. Inthe manner described earlier this transmission with free stroke preventsthe plunger 54 being unintentionally pushed too far in the direction ofthe needle 53 after the taking of the sample, which would result in thecollected cell material 54 being pressed out of the needle 54 again.

The device 50 is also provided with ratchet means 60 for temporarilyblocking the spring 57 counter to the force of the spring 57 in the mostoutermost position of the plunger 54. The ratchet means 60 are formed bytwo ratchet arms 61, 62 situated diametrically opposed to one another onthe thumb rest 56 and a sleeve 63 provided with cams 65, 66 which ispushed over the cylinder 51. A freely slidable ring 64 is arranged onthe sleeve 63. The ratchet arms 61, 62 bear on their end a ratchet 68which can grip behind the first cam 65 and second cam 66 of the sleeve63. The foremost cam 65 is provided on its rear side with a slopingsurface 67 so that the ratchet 64 can easily slide over it during themovement, to be further described, from right to left as seen in FIG. 4.

The working of the device 50 is hereafter further elucidated withreference to the FIGS. 5a-e.

As preparation for the operation of taking a sample the plunger 54 inits outermost position is pressed into contact with the end of thecylinder 51 bearing the coupling element. This is shown in FIG. 5. Thedevice 50 is held in the usual manner for an injection syringe, wherebythe index finger and middle finger grip on either side of the cylinderbehind the finger rests 69 and the thumb is held on the thumb rest 56.By pressing in the thumb rest 56 the cams 58 at the end of the actuatingshaft 55 come up against the front end of the slot 59 so that theplunger 54 can be pressed completely forwards. The ratchets 68 canhereby slide onto the slide ring 64. The pressure on the thumb rest 56is subsequently lessened as a result of which the spring 57 moves theactuating shaft to the right together with the component parts forming awhole with it. The slide ring 63 is hereby held in position so that itcannot co-slide. The ratchets 68 slide as a result off the ring 64 andare pressed inward through the resilient force of the ratchet arms 61,62, thereby falling behind the first cam 65. This situation is shown inFIG. 5b. In this situation the needle is inserted. This can take placein the manner described earlier with sensitivity since no forces need tobe further exerted on the device than are necessary for the insertion ofthe needle. Once the needle has been inserted in the required manner aforce is once again applied to the thumb grip 56 with the thumb. Theratchets 68 of the ratchet arms 61, 62 consequently slide onto the slidering 64 again. This situation is shown in FIG. 5c. By now once againrelieving the pressure on the thumb grip 56 the actuating shaft 55 andthe parts forming a whole therewith slide to the right as seen in FIG.5. The ratchets 65 hereby take the slide ring 64 with them. The slidering 64 thereby comes to a stop against the first cam 65. This positionis shown in FIG. 5d. The cams 58 have hereby come into contact with therear end of the slots 59. By now further reducing the pressure of thethumb the cams 68 slide from the ring and over the cam 65 so that theactuating shaft 55 can move further to the rear and can thereby pull theplunger 54 along with it. In this situation as shown in FIG. 5e thesubcutaneous tissue cells can be collected in the manner describedabove.

When this operation has been completed the thumb rest 56 is againpressed to the left whereby the ends of the ratchets 68 move over thesloping edge 67 on the cam 65. With further movement to the left thering 64 is pushed aside and the ratchets 68 can fall behind the cam 65.Thus reached again is the situation shown in FIG. 5b. The plunger 54 isonly moved back under the influence of the underpressure created at thefront side thereof so that in the situation thus achieved no more forceswill act on the plunger 54, thereby preventing the collected cellmaterial being pressed outward out of the needle or being sucked inwardinto the cylinder. With the ratchets 68 in engagement with the cam 65the whole device can be withdrawn.

The second cam serves as end stop for the cams 68 so as to prevent anunintended manipulation causing the shaft with the plunger to come outof the cylinder under the influence of the action of the spring 57. Whenthe spring 57 is dimensioned such that it is completely expanded beforethe shaft is withdrawn from the cylinder the cam 65 can be omitted. Asshown the ratchet means comprise the separate sleeve 63 which can slidewith a light grip fitting onto a cylinder of a standard disposablesyringe. For the manufacture of the device according to the invention inthis embodiment partial use can be made therefore of components whichare already manufactured for standard disposable injection syringes. Itis of course also possible to integrate a ratchet device with acylinder.

The invention is not limited to the embodiments shown in the figures. Itis important that during the puncturing the underpressure is developedby previously introduced energy. The biasing means can work in manyother ways instead of with resilient force, such as for example with gaspressure. The preferably applied ratchet can be manually operated orautomatically acting. Optionally the biasing means can take anadjustable form. In the case of use of springs, such as the springs 21,as biasing means, an adjustable end stop for these springs can beapplied which results in it becoming possible to adjust the equilibriumunderpressure occurring during use as required.

I claim:
 1. Apparatus for taking a sample of subcutaneous tissue cellsfrom a body comprising a disposable injection syringe with a cylinder; aplunger slidably arranged in said cylinder and connected to an actuatingshaft protruding outside said cylinder at one end, and connected to acoupling element at the opposite end of said cylinder for the couplingthereto of an injection needle; and further pulling means for theexerting of a force on said plunger in the direction away from saidcoupling element, said pulling means including on one side energytransmitting biasing means coupled to said cylinder which exerts atensile force on said plunger such that after a movement of said plungerin the order of magnitude of 1 cm from an outermost position in contactwith the end of said cylinder bearing said coupling element, the tensileforce on said plunger lies in the order of magnitude of 10 Newton timesthe diameter of said cylinder in cm².
 2. The apparatus of claim 1 whichincludes ratcheting means for temporarily blocking said biasing means inan outermost position of the plunger counter to the force of saidbiasing means.
 3. Apparatus as claimed in any of the above claimswherein the apparatus is embodied in its entirety as a disposable devicefor once-only use.
 4. Apparatus as claimed in claims 1 or 2 whichincludes a holder for said disposable injection syringe, said holderincluding a first holder part with first gripping means for thecylinder, and a second holder part slidably connected to said firstholder part with second gripping means for said actuating shaft andwhereby said biasing means are connected to said first and second holderparts and force said first and second gripping means away from oneanother.
 5. Apparatus as claimed in claim 4 wherein said first andsecond gripping means are arranged such that they can grip on firstfinger rests on respectively the cylinder and the activating shaft ofsaid disposable injection syringe.
 6. Apparatus as claimed in claim 4 or5 wherein said first holder part includes a passage opening for saidcylinder at the end of said cylinder away from said first grippingmeans.
 7. Apparatus as claimed in any of the claims 4,5 or 6 whichincludes second finger rests at a distance from said first finger restson the side away from said first finger rests for said actuating shaft.8. The apparatus of claim 1 or 2 which includes a finger rest foractuating said plunger, said finger rest being coupled to said plungerby a transmission with a free stroke and that said biasing means arecoupled directly with said finger rest.
 9. The apparatus as claimed inany of the above claims in which said biasing means is a spring.